Control of incompetent formations with thickened acid-settable resin compositions

ABSTRACT

A method and composition is provided for positioning a polymeric material having particulate matter disposed therein in a subterranean formation penetrated by a wellbore. The composition consists essentially of a hydrocarbon oil, a quaternary salt of an essentially undegraded, cellulose sulfate, solid particulate matter in an amount equal to from about 0.25 to about 22 pounds of particulate matter per gallon of hydrocarbon oil and an acid-settable thermosetting resin in an amount equal to from about 0.1 to about 5.0 gallons per cubic foot of particulate material. The composition is placed in contact with a subterranean formation in a wellbore by a method comprising injecting a first mixture consisting essentially of said quaternary salt of an essentially undegraded cellulose sulfate mixed with hydrocarbon oil followed by the injection of the composition with a post injection of an additional quantity of the quaternary salt in oil.

This is a division of application Ser. No. 739,216, filed Nov. 5, 1976now U.S. Pat. No. 4,085,801.

BACKGROUND OF THE INVENTION

This invention relates to control of incompetent subterranean formationspenetrated by wellbores.

In the production of fluids, such as oil, gas, water, etc, fromsubterranean formations, a number of difficulties are encountered whenthe well through which the fluids are produced penetrates an incompetentor unconsolidated subterranean formation. Such formations frequently arecomposed of incompetent sand, and the grains of the sand becomeentrained in the fluid being produced and are carried into the wellbore.The result of such entrainment, among other things, is the abrasion ofthe pumping equipment in the wellbore, clogging of the strainers, sandbridging in the tubing, plugging of surface flow lines, filling ofoil-water separators, and the sanding in of the cavity immediatelyadjacent the strainers. These results, in turn, ultimately cause a sharpdecrease in the rate of production of hydrocarbon fluids and increasedmaintenance costs.

Various solutions to this problem have been proposed. For example,gravel and sand packs employing the injection of particulate solids inthickened hydrocarbons wherein the thickening agent is an aluminum soapof fatty acids, finely-divided silica, bentonite, certain other soaps(NAPALM) and the like have been employed as are disclosed by U.S. Pat.Nos. 2,906,338, 2,978,024, 3,498,380 and 3,064,730.

One of the more successful solutions to the incompetent formationproblem has been the use of polymeric resins for injection into thewellbore in combination with solid particulate matter to form aconsolidated area adjacent the wellbore in the sand producing zone. Suchtechniques are shown in U.S. Pat. No. 3,378,071, patented Apr. 16, 1968,by Derry D. Sparlin and assigned to Continental Oil Company as well asU.S. Pat. No. 3,692,116 by Derry Sparlin and assigned to Continental OilCompany. U.S. Pat. No. 3,378,071 and U.S. Pat. No. 3,692,116 are herebyincorporated by reference.

Gelled water systems are presently used for placing gravel and plasticagainst subterranean formations for controlling incompetent sand. It isdesirable in many instances to use a gelled oil system in manyformations wherein the oils are more compatible with the subterraneanenvironment than water. Water in some formations impairs the productionof fluids from the well by forming emulsions with the oil in theformation, hydrating shales or clays in the formation and the like.Gelled oil prevents these problems and is diluted by the produced crudeoil which facilitates the initial production of oil from the well afterwell treatment.

A further patent relating to a similar process is U.S. Pat. No.3,391,738, patented July 9, 1968, by Derry D. Sparlin and assigned toContinental Oil Company. U.S. Pat. No. 3,391,738 is hereby incorporatedby reference.

In such processes, the mixture injected into the formation toconsolidate the portions of the subterranean formations surrounding thewellbore comprises a polymeric resin which polymerizes in situ and, inmany instances, contains particulate material. In the use of suchprocesses, it has long been considered desirable that a gelled oil, orthe like, be available for suspending the sand and unpolymerized resinsduring injection into the wellbore. Such a gelled oil has beenunavailable to the art heretofore, since the gelling agents commonlyused have been found to be incompatible with the polymeric resinsinjected. As a result, the art has used viscous oils and the like tosuspend the particulate matter in solution with the polymeric resins.

The use of viscous oils and the like results in difficulty in removingthe viscous oil from the formation once the resins have polymerized.Accordingly, considerable time has been devoted to attempted developmentof gelled oil mixtures which are capable of suspending the particulatematter for injection into the wellbore in solution with the polymericresins without adversely affecting the performance of the resins.

OBJECTS OF THE INVENTION

An object of the invention is to control an incompetent formation.

A further object is to overcome deficiencies in prior art methods ofcontrolling incompetent formations.

A further object is to provide gelled compositions for controllingincompetent formations.

These, and other objects and advantages will appear from the followingdescription of the embodiments of the invention, and the most novelfeatures, will be particularly pointed out hereinafter in connectionwith the appended claims.

SUMMARY OF THE INVENTION

Such objectives are achieved by the use of a composition for positioninga polymeric material having particulate matter disposed thereincontacting a subterranean formation penetrated by a wellbore wherein thecomposition consists essentially of

(a) a hydrocarbon oil,

(b) a quaternary ammonium salt of cellulose sulfate.,

the quaternary group of said quaternary salt of cellulose sulfatecontaining at least 16 carbon atoms and being present in saidcomposition in an amount sufficient to produce a minimum apparentviscosity in said composition of at least 50 cps but less than 5000 cpsat the injection temperature and pressure, and an apparent viscosity insaid composition at bottom hole conditions of at least 25 cps;

(c) finely-divided particulate material in an amount equal to from about0.25 to about 22 pounds of particulate material per gallon of said oil;and,

(d) an acid-settable liquid thermosetting resin in an amount equal tofrom about 0.1 to about 5.0 gallons per ft³ of said particulatematerial.

Quaternary salts of cellulose sulfates are effective in gellinghydrocarbon oils for use in suspending finely-divided solid particulatematter for injection into subterranean formations, and quaternary saltsof cellulose sulfates also have a beneficial effect upon the resins usedto form the solid organic polymeric material in the subterraneanformation when the resins are chosen from the group consisting ofacid-settable liquid thermosetting resins.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Some suitable resins are disclosed in U.S. Pat. No. 3,391,738incorporated herein by reference, especially in Columns 3 through 7.Some preferred resins are acid-settable polyepoxides, acid-settablepolyesters, phenolic novolacs, hydroxy aryl-aldehydes, furans, furfurylalcohol resins, and acid-settable polyurethanes. Of these, the phenolicnovolacs, hydroxy aryl-aldehydes, furans, and furfuryl alcohol resinsare preferred. The resin is desirably present in an amount equal to fromabout 0.1 to 5.0 gallons per ft₃ of solid particulate material. Verydesirable results are obtained when about 1.0 to 2.0 gallons per ft³ ofsolid particulate matter is used.

The resin may be added in a diluted form containing from 10 to 90percent inert diluent. The amounts of resin stated above refer to 100percent resin and reactive resin components and do not include the inertdiluents.

In the practice of the present invention from about 0.25 to about 22pounds of solid particulate material per gallon of oil is useful withthe more commonly used ranges varying from about 10 to about 15 poundsof solid particulate material per gallon of oil.

The quaternary salts of cellulose sulfate are desirably present in anamount sufficient to result in an apparent viscosity of the compositionat surface conditions of at least about 50 cps but not more than 5000cps. At least 50 cps viscosity is desirable to maintain the particulatematter in suspension, but above about 5000 cps, it becomes difficult tohandle the composition. The slurry can be heated at the surface toreduce its viscosity so that it can be easily pumped and will have thedesired viscosity at the bottom of a hot well. As the slurry is pumpedinto contact with the subterranean formation, the geothermal temperatureincreases, causing a reduction in viscosity. Desirably, the compositionhas a minimum viscosity of at least about 25 cps at bottom-holeconditions in order that the solid particulate matter may be adequatelysuspended in the composition. Such is necessary to insure that the solidparticulate matter, which in many instances is sand, is adequatelysuspended as it is packed contacting the formation around the wellbore.The concentration of quaternary salt required to obtain the desiredviscosity will vary with the physical and chemical properties of the oiland the like and thus must be determined for the specific oil used. Suchdeterminations are well within the skill of those in the art; however,in many instances, concentrations from about 0.03 to about 5.0 weightpercent quaternary salt based on the weight of the composition will befound effective.

The viscosity of the oil gelled with quaternary salt is reduced by theaddition of acid in combination with time and temperature. Accordingly,those skilled in the art may readily determine the concentration andtype of acids required to maintain the proper oil viscosity for the timeinterval necessary to carry the sand and resin slurry into contact withthe formation and cause an oil viscosity reduction to occur subsequentlyduring the time interval necessary for the resin to harden but beforethe well is put on production. In some instances, especially whererelatively low subterranean temperatures (below 150° F.) exist in theproducing interval, additional acid may be injected to aid in rapidhardening of the plastic and reduction of oil viscosities. Oil solubleacids, such as trichloroacetic acid, aluminum chloride red oil, and thelike may be used. The slurry of resin, sand, and gelled oil may beintentionally prepared and pumped without acid catalysts or withinsufficient catalyst to cause the resin to harden, and thereafter anoil soluble acid or acid oil may be pumped into the resin-sand mass tocatalyze the polymerization of the resin and reduce the oil viscosity.Numerous such variations and modifications are possible within the scopeof the present invention.

The hydrocarbon oil employed can be any suitable refined or crude oilstream, such as diesel oil, kerosene, light crude, distillates, and thelike. It is, however, desirable that the oil be substantially neutral.

The finely-divided solid particulate material used, in many instances,will be sand. The sand is normally in a finely-divided form, such as forinstance, of a U.S. standard mesh size between 10 and 100. Othermaterials which may be used include nutshells, peach pits, brittlesynthetic resins, gilsonite, coke, and similar solid material.

It is often desirable that the mixture which is contacted with theincompetent formation contain a coupling agent. The coupling agent canbe any material known to promote adhesion of an organic polymer tomineral matter. In particular, anyone or combination of the couplingagents disclosed by U.S. Pat. No. 3,285,339 (herein incorporated byreference) can be employed. A particularly presently preferred couplingagent is gamma aminopropyltriethoxysilane. Often in the range of about0.002 to 0.04 parts by weight of coupling agent can be employed for eachpart by weight of organic polymer. Below about 0.002 parts by weight ofcoupling agent is largely ineffective while quantities above about 0.04parts by weight become uneconomic. More preferably, in the range ofabout 0.01 to 0.02 parts by weight of coupling agent are employed foreach part by weight of organic polymer to provide optimum effectivenessat an economically feasible cost.

The quaternary ammonium cellulose sulfate salts are prepared by meansknown to those skilled in the art, such as disclosed, for instance, inU.S. Pat. No. 3,726,796, issued Apr. 10, 1973, to Schweiger and assignedto Kelco Company. U.S. Pat. No. 3,726,796 is hereby incorporated byreference.

The quaternary ammonium cellulose sulfate salts are derivatives of acolloidal cellulose sulfate having a degree of substitution (D.S.) of atleast about 2, e.g., such as 1.8; having a viscosity in excess of 20 cpsat a one percent concentration in an aqueous media as measured by aBrookfield Synchro-Lectric Viscometer, Model LVF, at 60 rpm and atemperature of 25° C. and being further characterized as reactive withpotassium ions in aqueous media to form a thermoreversible gel. Thequaternary ammonium salt which is reacted with the colloidal cellulosesulfate contains four organic radicals attached to the nitrogen atom.The number of carbon atoms present in all of the organic substituentgroups should total about 16 or more in order to impart suitablesolubility characteristics to the resulting quaternary ammonium salt ofthe cellulose sulfate.

The reaction to form the quaternary ammonium cellulose sulfate salt isconducted in the presence of water, and there is optionally present alower alcohol. A preferred lower alcohol is methanol since it is quitemiscible with water and is cheap and readily available. The reaction isgenerally conducted by dissolving in water, preferably at a pH of about7 or higher, a water-soluble salt of the colloidal cellulose sulfateafter which there is optionally added a lower alcohol followed by theaddition of a quaternary ammonium salt. The reaction may be conducted atroom temperature or higher temperatures such as about 50° C. to 70° C.and preferably with agitation of the reaction mixture. The reaction goesalmost instantaneously to give a nearly quantitative yield of thequaternary ammonium derivative of the colloidal cellulose sulfate. Theproduct precipitates from the mother liquor and is removed and is thenwashed and dried.

The colloidal cellulose sulfate reactant used in the reaction may be awater-soluble salt of cellulose sulfate, such as the sodium, ammonium,lithium, or potassium salt. The nature of the ion, such as sodium, whichis present in the cellulose sulfate starting material can, of course, bevaried so long as the cellulose sulfate salt is water soluble. Thequaternary ammonium reactant is preferably a halogen salt, such as achloride, bromide, or an iodide.

If desired, the quaternary ammonium salts of the colloidal cellulosesulfate may be formed by reaction of the free sulfuric acid ester of thecolloidal cellulose sulfate rather than reaction of a water-soluble saltthereof. When the cellulose sulfate reactant is in the form of the freesulfuric acid ester, the quaternary ammonium ion is supplied by use ofthe corresponding quaternary ammonium hydroxide as a reactant.

Preferably, the quaternary ammonium salt or quaternary ammonium base, asthe case may be, is employed in slight excess in forming the quaternaryammonium salt of a colloidal cellulose sulfate as described above. Amolar excess of quaternary ammonium reactant of 0.1 to 0.3 or greaterhas a tendency to drive the reaction to essential completion. This isdesirable because the colloidal cellulose sulfate is the more expensiveof the reactants. Completion of the reaction can be readily determinedby visual observation of the mother liquor. As the quaternary ammoniumcellulose sulfate product is formed, it coagulates and leaves thesolution such that the remaining mother liquor becomes nearly clear andloses that portion of its viscosity which was contributed to it by thecellulose sulfate reactant. Further, the use of a slight molar excess ofthe quaternary ammonium reactant, e.g., 0.1 to 0.3, has, in general,been found to improve the solubility characteristics of the resultingproducts in a hydrocarbon oil as employed in the present invention.

The colloidal cellulose sulfate is prepared by reaction of cellulosewith a complex of sulfur trioxide and a lower N-dialkyl amide. Thecellulose is presoaked prior to the sulfation reaction by the additionthereto of at least an equal weight of the same lower N-dialkyl amide.Preferably the N-dialkyl amide is dimethyl formamide, although there mayalso be used diethyl formamide, dimethyl acetamide, diethyl acetamide,and dimethyl propionamide. An excess of the N-dialkyl amide ispreferably present in the sulfation complex in addition to the premixingof the cellulose with at least an equal amount by weight of theN-dialkyl amide used in preparing the complex.

In forming the essentially undegraded colloidal cellulose sulfate, thesulfation complex which contains sulfur trioxide and a lower N-dialkylamide at a weight ratio of about 1 to 1 should be present in thereaction mixture in an amount which is about 1 to 8 times the weight ofthe cellulose. The term "cellulose" includes cellulose derived fromvarious sources and in various forms, such as chemically treated cottonlinters, cellulose derived from wood, etc.

In reaction of the sulfation complex with cellulose, as described above,a reaction temperature of about 0° C. to about 25° C. is suitable, andpreferably the sulfation reaction is conducted at a temperature belowabout 15° C. The reaction time for relatively complete esterificationcan range from less than 1 hour up to several hours, depending upon thereaction temperature and the relative concentrations of the reactants.

One category of quaternary ammonium cellulose sulfate compounds whichcan be used in our invention is denoted (I) in which there are two longchains, i.e. from about C₁₀ to about C₁₈, alkyl groups attached to thenitrogen atom in addition to two methyl groups. Examples of suchquaternary ammonium cellulose sulfates are dimethyl dilauryl ammoniumcellulose sulfate, dimethyl distearyl ammonium cellulose sulfate, andcompounds containing mixed long-chain alkyl groups, such as dimethyldi(mixed palmityl, myristyl, and stearyl) ammonium cellulose sulfatewhich may also be called dimethyl di(hydrogenated tallow) ammoniumcellulose sulfate. Still another example of a di(mixed alkyl) dimethylammonium cellulose sulfate is dimethyl di(tallow) ammonium cellulosesulfate in which the mixed long-chain alkyl groups contain some degreeof unsaturation.

A secondary category (II) of quaternary ammonium cellulose sulfates arethose in which three methyl groups are bonded to the nitrogen atom,together with one long-chain alkyl group, i.e., about C₁₄ to C₁₈.

Typical of such products are trimethyl tallow ammonium cellulosesulfate, trimethyl hydrogenated tallow ammonium cellulose sulfate,trimethyl stearyl ammonium cellulose sulfate, and trimethyl tall oilammonium cellulose sulfate.

Still other categories of quaternary ammonium cellulose sulfates are(III) dimethyl monoalkyl (about C₁₂ -C₁₈) monoaromatic ammoniumcellulose sulfates; (IV) diaromatic monoalkyl (about C₁₂ -C₁₈) methylammonium cellulose sulfates, and (V) methyl trialkyl (about C₈ -C₁₈)ammonium cellulose sulfates. An example of a product in category (III)is dimethyl phenyl stearyl ammonium cellulose sulfate, while an exampleof a material in category (VI) is methyl tricaprylyl ammonium cellulosesulfate. Of the quaternary ammonium cellulose sulfates defined above,the materials in categories (I), (IV), AND (V) are preferred for use inthe present invention.

The aromatic groups present in the compounds denoted (IV) above aremonocyclic aromatic hydrocarbon groups containing from 6 to about 18carbon atoms. Typical of such groups are phenyl, stearylphenyl,laurylphenyl, and dimethylphenyl groups.

The materials may be mixed in any desired sequence so long as the oil,quaternary ammonium cellulose sulfate salt, resins and resin componentssuch as catalysts, coupling agents and the like, and solid particulatematerial are blended into a relatively homogeneous mass prior toinjection.

In the use of the composition of the present invention, a gelled oilmixture comprising a hydrocarbon oil and quaternary ammonium cellulosesulfate salt is prepared to have a viscosity substantially the same asthe viscosity of the gelled oil portion of the composition comprisingthe hydrocarbon oil, quaternary salt of cellulose sulfate, solidparticulate matter, and polymer resins. The gelled oil mixture soprepared is injected immediately ahead of the composition containing thequaternary salt, hydrocarbon oil, particulate matter, and polymer resinsso that the composition is maintained at substantially a constantviscosity during injection. In other words, contact with a leadingfluid, such as water, oil, or the like, tends to result in mixing thecomposition with the leading fluid thereby resulting in difficulties inmaintaining the resins and particulate matter in suspension. Suchproblems are obviated by the use of the leading mixture containinghydrocarbon oil and quaternary salt.

The composition of the present invention is then injected, and atrailing slug comprising a gelled oil mixture of hydrocarbon oil andquaternary salt in substantially the same proportions as used initiallyis injected. Such is necessary to prevent mixing of the trailingportions of the composition with a trailing fluid and the like.

The trailing gelled oil mixture is commonly followed with a wiper plugwhich is followed by oil, water, or the like. The fluid trailing thewiper plug is used to force liquid components of the composition intothe formation, thereby resulting in positioning the polymer and saidabout the wellbore to form a consolidated sheath in the zone of interestcontacting the formation. In the practice of the present invention,water, oil, or the like is injected behind the wiper plug to force thecomposition into the formation until such time as the polymer and sandhave entered the formation about the wellbore. The entry of thecomposition into the formation about the wellbore is indicated by asudden increase in the pumping pressure necessary to pump fluid into thewellbore behind the wiper plug. Upon observing the pressure increase,pumping is stopped for a sufficient period of time to allow the resin topolymerize.

Optionally, a bit, scraper, or the like is then passed down the wellboreto remove the excess polymer and particulate material from the inside ofthe wellbore, and thereafter the well is ready for a return toproduction or the like.

Having thus described certain preferred embodiments of the presentinvention, it is pointed out that many variations and modifications arepossible within the scope of the present invention, and it isanticipated that many such variations and modifications may beconsidered obvious and desirable by those skilled in the art upon areview of the foregoing description of preferred embodiments and thefollowing examples.

EXAMPLE I

Samples of diesel oil were gelled by adding SOLOID.sup.(1) to No. 1diesel oil and shearing it at the lowest speed in a Waring Blender untilgelation occurred. Slurries were then prepared with 125 ml gelled dieseloil, 300 g 40-60 mesh sand, 25 ml resin, 2.5 ml catalyst, and 0.2 mlSILANE A1100..sup.(2) All samples prepared made good pumpable slurriesthat could be used for sand control treatments in wells.

Samples of the slurries were poured into 7/8-inch diameter by 6-inchlong tygon tubes and cured in a water bath at 160° F. overnight. Allsamples prepared with Epon 828.sup.(3) epoxy resin and DETA.sup.(4)catalyst did not harden. Apparently, the SOLOID interfered with thepolymerization of the epoxy resin and prevented it from consolidatingthe sand. All samples that contained 33 percent DUREZ 7421A.sup.(5)resin in furfuryl alcohol and 50 percent aqueous hypophosphorous aciddid harden as shown below:

    ______________________________________                                                            Average Compressive                                       Gelled Oil          Strength (PSI)                                            ______________________________________                                        Pale Oil 400.sup.(1)                                                                              414                                                       1 Percent SOLOID in Diesel Oil                                                                    731                                                       3/4 Percent SOLOID in Diesel Oil                                                                  647                                                       1/2 Percent SOLOID in Disel Oil                                                                   694                                                       ______________________________________                                         .sup.(1) Pale Oil - a refined paraffinic mineral oil having an API gravit     of 30.0, a C/H ratio of 6.3, a molecular weight 482, a SSU viscosity at       100° F of 399.3, at 210° F of 57.61, a pour point of            0° F, and an ASTM color of 2.                                     

These data demonstrate that the gelled oil based systems having acidcatalysts solidify to form quite satisfactory structures whereas thebased catalyzed compositions do not solidify and are unsuitable.

Diesel oil gelled with SOLOID maintains its viscosity after exposure to160° F. for at least 19 hours, but with the addition of 1 percent byweight of 50 percent aqueous hypophosphorous acid, the viscosity isreduced significantly with time, which will allow easy cleanup of theoil after the treatment. For instance, the initial viscosity of 2percent SOLOID in diesel oil with 1 percent acid is 47 cp at roomtemperature measured with a viscometer.sup.(2) at 300 rpm. After beingcured at 160° F. for 6 hours, the room temperature viscosity of the samesample was 13 cp. The same gelled diesel oil with 2 percent SOLOIDwithout any acid had an initial viscosity of 36 cp and after curing at160° F. for 6 hours had 84 cp viscosity at room temperature.

Other oil gelling agents have been tested for the purpose of suspendingsand and resins for treating wells to control formation sand productionbut were found to be incompatible with the resins.

EXAMPLE 2

In a test using CAB-O-SIL.sup.(1) as a gelling agent, 125 ml of gelleddiesel oil, 300 g of 40-60 mesh sand, 50 ml of 80 percent DUREZ.sup.(2)7421A resin in furfuryl alcohol, 10 ml 12119 DUREZ.sup.(2) catalyst, and0.2 ml SILANE A1100 were mixed. Immediately after adding the SILANEA1100, the gel broke, and the oil would not suspend the sand. Thismixture, therefore, could not be pumped into a wellbore.

Another test used Sodium Palmitate and NaOH to gel the diesel oil. Aslurry was mixed with 125 ml of the gelled diesel oil, 300 g 40-60 meshsand, 50 ml of Dowell's K70-K71.sup.(3) resin, 3 ml 25 percent aqueousNaOH, and 0.2 ml SILANE A1100. The K70-K71 resin was added last to thisslurry, and as it was added, the gel broke, rendering the slurryunpumpable.

Another slurry was prepared using the same gelled diesel oil as abovewherein 125 ml of the gelled oil was mixed with 300 g of 40-60 meshsand, 25 ml of 80%, DUREZ 7421A resin in furfuryl alcohol, 1 ml of DUREZ12119 catalyst, and 0.2 ml SILANE A1100. The gel broke immediately whenthe resin was added.

Another test used Aluminum Stearate and NaOH to gel the diesel oil. Oneslurry of 125 ml gelled diesel oil, 300 g 40-60 mesh sand, 25 ml 80percent DUREZ 7421A resin in furfuryl alcohol, 1 ml DUREZ 12119catalyst, and 0.2 ml SILANE A1100 was prepared. Another slurry was mixedusing 125 ml gelled diesel oil, 300 g 40-60 mesh sand, 25 ml 33 percent7421A resin in furfuryl alcohol, 1 ml DUREZ 12119 catalyst, and 0.2 mlSILANE A1100. The gelled diesel oil in these slurries maintained itsviscosity so that they were pumpable, and they were cured at 120° F. for3 days. Neither composition had any measurable compressive strength.Thus, the Aluminum Stearate system apparently interfered with the normalreaction of the resins.

Diesel oil gelled with BAROGEL.sup.(1) was also tested by mixing 25 gBAROGEL in 75 ml diesel oil in a Waring Blender for 30 minutes, adding10 ml methanol and 725 ml diesel oil, and mixing another 30 minutes. Theresult was an extremely thick, grease-like gel that needed to be dilutedwith diesel oil to make a practical sand control slurry. A test wasperformed by adding 300 g of 40-60 mesh sand to 100 ml of the gelleddiesel oil diluted with 25 ml of diesel oil. Then 25 ml of 80 percentDUREZ 7421A resin in furfuryl alcohol, 1 ml DUREZ 12119 catalyst, and0.2 ml SILANE A1100 were added to the slurry. This made a pumpableslurry, but after four days' curing at 160° F., the resin had nothardened. Apparently, the BAROGEL interfered with the normal reaction ofthe resin.

Further attempts to make the BAROGEL system work also resulted infailure of the resin to harden. In one attempt, 300 ml of diesel oil wasblended with 25 ml of BAROGEL and 5 ml methanol for 30 minutes in aWaring Blender. A slurry was then made with 100 ml of the resultinggelled diesel oil diluted with 100 ml of diesel oil to which was added300 g of 40-60 mesh sand, 25 ml 80 percent DUREZ 7421A resin in furfurylalcohol, 2 ml 12119 DUREZ accelerator, and 0.2 ml SILANE A1100. Thisslurry was cured at 160° F. for four days with the same result, eventhough the catalyst concentration was doubled.

Another attempt was made by mixing 25 g of BAROGEL and 300 g diesel oilin the Waring Blender for 30 minutes, then adding 5 ml methanol and 400ml diesel oil. This made a thinner fluid but was still capable ofsuspending the sand. To 100 ml of this gelled diesel oil was added 300 gof 40-60 mesh sand, 25 ml 80 percent DUREZ 7421A resin in furfurylalcohol, 2 ml 12119 DUREZ catalyst, and 0.2 ml SILANE A1100. This slurrywas also cured at 160° F. for 4 days, and the resin again did not set.

These tests indicate that conventional oil gelling agents cannot be usedin conjunction with resins, catalysts, or coupling agents (such asSILANE) required to make a slurry that can be easily pumped into a welland placed in contact with a subterranean formation where, with time andtemperature conditions normally encountered, the resin will harden,forming a permeable consolidated sand filter that will stop formationsand movement and allow formation fluids to be produced. The compositionof the present invention is effective providing a means of accomplishingthese ends when used as described herein.

EXAMPLE 3

460 gallons of diesel fuel and 32.2 pounds of SOLOID thickener is mixeduntil the viscosity is about 1000 cps at a shear rate of 10 sec⁻¹ toproduce a gelled oil. 250 gallons of the gelled oil is left in themixer, and the remaining 210 gallons is placed in a storage tank. 3,750pounds of 40-60 U.S. mesh sand is mixed with the 250 gallons of gelledoil. 37.5 pounds of a resin consisting of 33 weight percentphenolformaldehyde and 67 weight percent furfuryl alcohol, 0.5 gallon ofSILANE A1100 and 3.75 gallons of a 50 weight percent aqueous solution ofhypophosphorus acid to form an injection mixture. After mixing for 10minutes, 126 gallons of gelled oil from the storage tank is pumped intothe well followed by the injection mixture, followed by 84 gallons ofgelled oil from the storage tank. The gelled oil is displaced by a wiperplug and followed with ungelled diesel oil. Additional diesel oil isinjected to displace the injection mixture into the formation and packthe sand tightly against the formation (indicated by a sudden increasein the pressure required to pump the diesel oil). Pumping is thenstopped and the resin allowed to harden. A bit and scraper is thenlowered into the well, and the excess plastic and sand is removed fromthe inside of the wellbore.

Having thus described the invention, we claim:
 1. A composition forpositioning an acid-settable polymeric material having particulatematter disposed therein in contact with a subterranean formationpenetrated by a wellbore, said composition consisting essentially of:(a)a substantially neutral hydrocarbon oil; (b) a quaternary ammonium saltof cellulose sulfate, the quaternary ammonium group of said quaternarysalt of cellulose sulfate containing at least 16 carbon atoms and beingpresent in said composition in an amount sufficient to produce a minimumapparent viscosity in said composition of at least 50 cps, but less than5000 cps at the injection temperature and pressure and an apparentminimum viscosity at bottom hole conditions of at least 25 cps; (c)finely-divided solid particulate material in an amount equal to fromabout 0.25 to about 22 pounds of particulate matter per gallon of saidoil; and, (d) an acid-settable liquid thermosetting resin in an amountequal to from about 0.1 to about 5.0 gallons per ft³ of said particulatematerial.
 2. The composition of claim 1 wherein said cellulose sulfateis an essentially undegraded cellulose sulfate and wherein thecomposition also contains an effective amount of a coupling agent. 3.The composition of claim 1 wherein said cellulose sulfate has a degreeof substitution of about 2.0 or higher, said cellulose sulfate having aviscosity of 20 cps or higher at 1.0 weight percent concentration in anaqueous media as measured by a Brookfield Synchro-Lectric Viscometer,Model LVF at 60 rpm and a temperature of 25° C., said cellulose sulfatebeing further characterized as reactive with potassium ions to form athermoreversible gel.
 4. The composition of claim 1 wherein saidquaternary ammonium portion of said quaternary salt contains:(a) twolong-chain alkyl groups each having from about 10 to about 18 carbonatoms and two methyl groups; (b) three methyl groups together with onelong-chain alkyl group having 14 to 18 carbon atoms; (c) two methylgroups, one alkyl group having 12-18 carbon atoms and one monocyclicaromatic hydrocarbon group having 6 to 18 carbon atoms; (d) twomonocyclic aromatic hydrocarbon groups with each of said aromatic groupscontaining from 6 to 18 carbon atoms, one alkyl group having 12-18carbon atoms and one methyl group; or (e) one methyl group and threelong-chain alkyl groups with each of said alkyl groups containing from 8to about 18 carbon atoms.
 5. The composition of claim 1 wherein saidcomposition consists essentially of:(a) a substantially neutralhydrocarbon oil; (b) a quaternary ammonium salt of an essentiallyundegraded, cellulose sulfate having a degree of substitution of about2.0 or higher, said cellulose sulfate having a viscosity of 20 cps orhigher at 1.0 weight percent concentration in an aqueous media asmeasured by a Brookfield Synchro-Lectric Viscometer, Model LVF at 60 rpmand a temperature of 25° C., said cellulose sulfate being furthercharacterized as reaction with potassium ions to form a thermoreversiblegel, said quaternary ammonium group of said salt containing:(1) twolong-chain alkyl groups each having from about 10 to about 18 carbonatoms and two methyl groups, (2) three methyl groups together with onelong-chain alkyl group having 14 to 18 carbon atoms; (3) two methylgroups, one alkyl group having 12-18 carbon atoms and one monocyclicaromatic hydrocarbon group having 6 to 18 carbon atoms; (4) twomonocyclic aromatic hydrocarbon groups with each of said aromatic groupscontaining from 6 to 18 carbon atoms, one alkyl group having 12-18carbon atoms and one methyl group; or, (5) one methyl group and threelong-chain alkyl groups with each of said alkyl groups containing from 8to about 18 carbon atoms said quaternary salt being present in saidcomposition in an amount sufficient to produce a minimum apparentviscosity in said composition of at least 50 cps but less than 5000 cpsat 25° C. and one atmosphere and an apparent viscosity in saidcomposition at bottom hole conditions of at least 25 cps; (c)finely-divided solid particulate material in an amount equal to fromabout 0.25 to about 22 pounds of particulate material per gallon of saidoil; and, (d) an acid-settable liquid thermosetting resin in an amountequal to from about 0.1 to about 5.0 gallons per ft³ of said particulatematerial.
 6. The composition of claim 1 wherein said resin is selectedfrom the group consisting of acid-settable polyepoxides, acid-settablepolyesters, phenolic novolaks, hydroxy aryl-aldehydes, furans, furfurylalcohol resins, and acid-settable polyurethanes and the composition alsocontains an effective amount of a coupling agent.
 7. The compoisition ofclaim 6 wherein said resin is selected from the group consisting ofphenolic novolaks, hydroxy aryl aldehydes, furans and furfuryl resins.8. The composition of claim 6 wherein said resin is present in an amountequal to from about 1.0 to about 2.0 gallons of resin per ft³ ofparticulate material.
 9. The composition of claim 6 wherein saidquaternary salt of cellulose sulfate is present in an amount equal tofrom 0.03 to about 5.0 weight percent based on the weight of thecomposition.
 10. The composition of claim 6 wherein the coupling agentis γ-aminopropyltriethoxysilane, the resin is a hydroxy aryl aldehyderesin, and the particulate material is siliceous sand.